Liquid cooling system for an internal combustion engine of a vehicle

ABSTRACT

The invention relates to a liquid cooling system (K) for an internal combustion engine ( 2 ) of a vehicle with a cylinder head ( 3 ) having as integrated exhaust manifold ( 7 ), wherein the cylinder head ( 3 ) has at least a first cooling chamber ( 5 ) for cooling areas adjoining a combustion chamber and at least a second cooling chamber ( 6 ) for cooling the exhaust manifold ( 7 ), wherein flows can pass through the first and second cooling chambers ( 5, 6 ) in parallel separately from one another. The cooling management can be improved in a simple manner if at least one oil cooler ( 14 ) and/or at least one vehicle heating element ( 15 ) is arranged in series with the second cooling chamber ( 6 ) in the cooling circuit ( 1 ).

The invention relates to a liquid cooling system for an internalcombustion engine of a vehicle with a cylinder head comprising anintegrated exhaust manifold, wherein the cylinder head has at least onefirst cooling space for cooling areas adjacent to a combustion chamberand at least one second cooling space for cooling the exhaust manifold,said first and second cooling spaces providing separate cooling flowpaths in parallel.

From U.S. Pat. Nr. 2005/0087154 A1 it is known to integrate the exhaustmanifold in the cylinder head. The main cooling space consisting of anupper and a lower partial cooling jacket is in thermal contact with theexhaust manifold.

EP 0 856 650 A1 describes a cooling system for an outboard engine wherethe exhaust ducts departing from the combustion chamber are curved inU-shape in the cylinder head, the flange areas for connecting theexhaust manifold being situated in the cylinder head plane. The exhaustmanifold is integrated in the cylinder head.

U.S. Pat. No. 7,051,685 B2 discloses a cylinder head with integratedexhaust manifold, where the exhaust manifold is surrounded by a firstand a second cooling jacket, the two cooling jackets being connected viaflow paths cast together with the cylinder head. The first and secondcooling jackets are positioned one above the other.

AT 500 442 B1 describes a cylinder head for an internal combustionengine with liquid cooling comprising a first central cooling space anda second cooling space surrounding an integrated exhaust manifold, wherethe coolant flow through the second cooling space may be controlledseparately from the coolant flow through the first cooling space.

From WO 2011/061248 A1 there is known a cylinder head for an internalcombustion engine with liquid cooling and with a liquid-cooled exhaustmanifold integrated in the cylinder head, where the cylinder head has atleast one first and one second cooling jacket through which coolantflows and where the region of the exhaust manifold is at least partiallysurrounded by the second cooling jacket. The first and second coolingjackets are flow-connected via at least one bore.

It is known to position the vehicle cooler and the oil cooler parallelto the cooling space of the exhaust manifold. In order to avoid coolingfailures a relatively expensive cooling system is required.

It is an object of the present invention to improve the coolingmanagement of an internal combustion engine of the initially mentionedkind in as simple a manner as possible.

According to the invention this object is achieved by proposing that atleast one oil cooler and/or at least one vehicle heating element bearranged in series with the second cooling space in the cooling circuit.

The oil cooler may be positioned in the cooling circuit upstream of thesecond cooling space, while the vehicle heating element is positioned inthe cooling circuit downstream of the second cooling space.

It is of particular advantage if a first partial cooling circuit leadingto the first cooling space and a second partial cooling circuit leadingto the second cooling space branch off the common main cooling circuitdownstream of a coolant pump.

Upstream of the coolant pump in an area where a main cooling circuitcoming from the coolant cooler and an auxiliary cooling circuitbypassing the coolant cooler meet, there may be provided a firstdouble-acting thermostatic valve.

The first cooling space is preferably connected by a first coolant linewith the auxiliary cooling circuit.

The second cooling space is advantageously connected via a secondcoolant line with the main cooling circuit and/or the auxiliary coolingcircuit, the second coolant line preferably including a vehicle heatingelement.

It may furthermore be provided that at least one third cooling spacelocated in the cylinder block be connected with the first cooling spacein the cylinder head by means of at least one transfer passage.Preferably, the third cooling space is connected with the main coolingcircuit via a third coolant line, the connection with the main coolingcircuit being located upstream of the coolant cooler. In a variant ofthe invention it is provided that in the third coolant line there islocated a single-acting thermostatic valve.

In another variant of the invention it is provided that the thirdcooling space be connected via a fourth coolant line with the auxiliarycooling circuit and/or the first coolant line. In the fourth coolantline there may be located a single-acting thermostatic valve. As analternative it would also be possible to position a second double-actingthermostatic valve at the crossing site of the first coolant line andthe fourth coolant line and the auxiliary cooling circuit.

The described variants permit a simple cooling management, the flowthrough the oil cooler and through the vehicle heating element having nonegative effects.

The invention will now be described in more detail with reference to theenclosed drawings. There is shown in

FIG. 1 to FIG. 3 a first variant of a liquid cooling system for aninternal combustion engine according to the invention;

FIG. 4 to FIG. 7 a second variant of a liquid cooling system for aninternal combustion engine according to the invention;

FIG. 8 to FIG. 11 a third variant of a liquid cooling system for aninternal combustion engine according to the invention; and in

FIG. 12 to FIG. 16 a fourth variant of a liquid cooling system for aninternal combustion engine according to the invention.

In the drawings deactivated parts of the liquid cooling system K areindicated by broken lines. Parts of equivalent function bear identicalreference numbers in each variant.

The drawings show in each case a liquid cooling system K with a coolingcircuit 1 for a vehicle with an internal combustion engine 2 withcylinder head 3 and cylinder block 4, comprising at least one firstcooling space 5 for cooling thermally critical areas adjacent to thecombustion chamber and at least one second cooling space 6 for coolingthe exhaust manifold 7 integrated in the cylinder head 3. At least onefurther cooling space 8 is provided in the cylinder block 4 for coolingthe cylinders 9.

KM indicates that part of the cooling system K pertaining to the engineside, while KF indicates the part pertaining to the vehicle side.

In the cooling circuit 1 coolant flow in the first and second coolingspace 5, 6 is hydraulically parallel, with a first partial coolingcircuit 10 serving the first cooling space 5 and a second partialcooling circuit 11 serving the second cooling space 6. The first andsecond partial cooling circuits 10, 11 branch off a common main line 13of the liquid cooling system K downstream of a coolant pump 12.

In the second partial cooling circuit 11 an oil cooler 14 is locatedupstream of the second cooling space 6 and a vehicle heating element 15is located downstream of the second cooling space 6. The vehicle heatingelement 15 may be deactivated by means of a bypass valve, which is notshown in the drawings.

In the area 16 where the main cooling circuit 18 coming from the coolantcooler 17 is joined by an auxiliary cooling circuit 19 bypassing thecoolant cooler 17, there is located a first double-acting thermostaticvalve 20 upstream of the coolant pump 12.

In the first three variants of the invention the first and the thirdcooling space 5, 8 are connected via at least one transfer passage 21.

The second cooling space 6 is connected via a second coolant line 23with the main cooling circuit 18 and/or with the auxiliary coolingcircuit 19, the vehicle heating element 15 being located in the secondcoolant line 23. The third cooling space 8 is connected with maincooling circuit 18 via a third coolant line 24, the connection 25 to themain cooling circuit 18 being located upstream of the coolant cooler 17.

In the variants shown in FIGS. 1 to 3 there is provided only onethermostat, i.e. the first double-acting thermostatic valve 20. In FIG.1 the first double-acting thermostatic valve 20 is shown in anintermediate position, in which both the main cooling circuit 18 and theauxiliary cooling circuit 19 are connected with the main line 13containing the coolant pump 12. FIG. 2 shows the situation when theinternal combustion engine is at operating temperature, the auxiliarycooling circuit 19 is deactivated and the entire coolant volume flowsthrough the main cooling circuit 18.

FIG. 3 shows the liquid cooling system K in the cold state, with themain cooling circuit 18 deactivated and the entire coolant volumeflowing through the auxiliary cooling circuit 19, bypassing the coolantcooler 17.

FIGS. 4 to 7 show a second variant of the invention with variousswitching possibilities, where in addition to the double-actingthermostatic valve 20 there is provided a single-acting thermostaticvalve 26 in the third coolant line 24. Furthermore, the first coolingspace 5 is connected with the auxiliary cooling circuit 19 via a firstcoolant line 22.

In FIG. 4 the first double-acting thermostatic valve 20 is in theintermediate position—in analogy to FIG. 1—and the single-actingthermostatic valve 26 is open. Thus coolant may flow unimpededly in themain cooling circuit 18 as well as in the auxiliary cooling circuit 19and in the third coolant line 24. In contrast to the first variant thecoolant may flow directly into the auxiliary cooling circuit 19 via thefirst coolant line 22.

FIG. 5 shows the situation when the internal combustion engine 2 is inthe cold state, the main cooling circuit 18 being closed by thedouble-acting thermostatic valve 20. The entire coolant volume flowsthrough the auxiliary cooling circuit 19, the coolant flowing directlyinto the auxiliary cooling circuit 19 via the first coolant line 22.

In FIG. 6 the internal combustion engine 2 is in the lower range ofoperational temperature, where the auxiliary cooling circuit 19 isclosed by the first double-acting thermostatic valve 20 while the maincooling circuit 18 is open. Due to closing of the single-actingthermostatic valve 26 cooling of the cylinder block 4 is deactivated.The coolant flows through the first cooling space 5 into the firstcoolant line 22 and via the free part 19 a of the auxiliary coolingcircuit 19 into the main cooling circuit 18 upstream of the coolantcooler 17. In parallel therewith the coolant flows through the secondpartial cooling circuit 11, through the oil cooler 14, the secondcooling space 6 and the vehicle heating element 15, and will arrive atthe coolant cooler 17 after having joined the coolant flow from thefirst partial cooling circuit 10.

FIG. 7 differs from FIG. 6 by the single-acting thermostatic valve 26now being open such that cooling of the cylinder block 4 is beingactivated as required in the medium to hot operational temperature rangeof the internal combustion engine 2. The coolant flows from the cylinderhead 3 via transfer passages 21 into the third cooling jacket 8 andleaves the cylinder block 4 via the third coolant line 24 in thedirection of main cooling circuit 18 to dissipate the absorbed heat inthe coolant cooler 17.

FIGS. 8 to 11 show a third variant of the invention with variousswitching possibilities, where the third cooling jacket 8 is connectedwith the auxiliary cooling circuit 19 via a fourth coolant line 27 andwith the first cooling space 5 via the first coolant line 22. Inaddition to the first double-acting thermostatic valve 20 there isprovided a single-acting thermostatic valve 28 in the third coolant line24. In this variant no transfer passages 21 are provided between thefirst and the third cooling space 5, 8, the function of these transferpassages being taken over by the first and fourth coolant line 22, 27.

In FIG. 8 the first double-acting thermostatic valve 20 is in itsintermediate position—in analogy to FIGS. 1 and 4—while thesingle-acting thermostatic valve 28 is open. Thus coolant may flowunimpededly in the main cooling circuit 18, as well as in the auxiliarycooling circuit 19 and in the third and fourth coolant line 24, 27.Unlike in the first variant the coolant may flow directly into theauxiliary cooling circuit 19 via the first coolant line 22, and may flowfrom the auxiliary cooling circuit 19 into the third cooling space 8 viathe fourth coolant line 27.

FIG. 9 shows the situation when the internal combustion engine 2 is inthe cold state: the main cooling circuit 18 is closed by thedouble-acting thermostatic valve 20 and the whole coolant volume isdirected through the auxiliary cooling circuit 19, flowing directly intothe auxiliary cooling circuit 19 via the first coolant line 22. Thesingle-acting thermostatic valve 28 is closed and inhibits flow into thefirst cooling space 8.

In FIG. 10 the internal combustion engine is shown in the loweroperational temperature range—analogous to FIG. 6—where the auxiliarycooling circuit 19 is closed by the first double-acting thermostaticvalve 20 and the main cooling circuit 18 is open. Due to closing of thesingle-acting thermostatic valve 28 cooling of the cylinder block 4 isdeactivated. The coolant thus flows through the first cooling space 5into the first coolant line 22 and reaches via the free part 19 a of theauxiliary cooling circuit 19 the main cooling circuit 18 upstream of thecoolant cooler 17. In parallel therewith the coolant flows through thesecond partial cooling circuit 11, through the oil cooler 14, the secondcooling space 6 and the vehicle heating element 15 and reaches thecoolant cooler 17 after joining the coolant flow of the first partialcooling circuit 10.

In FIG. 11 the single-acting thermostatic valve 28 is now open, andcooling of the cylinder block 4 is thus activated in the medium to hotoperational temperature range of the internal combustion engine 2. Thecoolant flows from the first cooling space 5 of the cylinder head 3 viathe first and the fourth coolant line 22, 27 into the third coolingspace 8 of the cylinder block 4 and leaves the cylinder block 4 via thethird coolant line 24 directed towards the main cooling circuit 18upstream of the coolant cooler 17.

FIGS. 12 to 16 show a fourth variant of the liquid cooling system K withvarious possibilities of switching. In a similar way as in the thirdvariant the third cooling space 8 is connected with the auxiliarycooling circuit 19 via a fourth coolant line 27 and with the firstcooling space 5 via the first coolant line 22. Instead of thesingle-acting thermostatic valve 28 there is now disposed, in additionto the first double-acting thermostatic valve 20, yet anotherdouble-acting thermostatic valve 29 at the crossing site 30 where thefirst and fourth coolant lines 22, 27 meet with the auxiliary coolingcircuit 19. In this case no other transfer passages 21 are providedbetween the first and the third cooling space 5, 8; the function oftransfer passages 21 is taken over by the first and fourth coolant lines22, 27.

In FIG. 12 both double-acting thermostatic valves 20, 29 are inintermediate positions. The coolant can thus flow unimpededly in themain cooling circuit 18 as well as in the auxiliary cooling circuit 19and in the third and fourth coolant line 24, 27. The coolant may flowvia the first coolant line 22 directly into the auxiliary coolingcircuit 19, or into the fourth coolant line 27 and from the auxiliarycooling circuit 19 via the fourth coolant line 27 into the third coolingspace 8.

FIG. 13 shows the situation when the internal combustion engine 2 is inthe cold state. The main cooling circuit 18 is closed by the firstdouble-acting thermostatic valve 20—the whole coolant volume passesthrough the auxiliary cooling circuit 19. Furthermore, the first andfourth coolant lines 22, 27 are closed by the second double-actingthermostatic valve 29, and thus there is no coolant flow through thefirst cooling space 5 and the third cooling space 8. The coolantcirculates only in the little circuit through the coolant line 11, theoil cooler 14, the second cooling space 6, the vehicle heating element15 and the auxiliary cooling circuit 19.

When the operational temperature of the internal combustion engine 2rises, the first coolant line 22 is opened by the second double-actingthermostatic valve 29, as shown in FIG. 14. This will enable coolantflow through the first cooling space 5 in the cylinder head 3, thecoolant leaving the first cooling space 5 via the first coolant line 22and flowing back to the coolant pump 12 via the auxiliary coolingcircuit 19.

Upon a further increase of the temperature of the internal combustionengine 2 the auxiliary cooling circuit 19 leading to the coolant pump 12is closed by the second double-acting thermostatic valve 29 between thecrossing site 30 and the meeting area 16, as shown in FIG. 15. Thecoolant leaving the first cooling space 5 through the first coolant line22 now flows through the free part 19 a of the auxiliary cooling circuit19 into the main cooling circuit 18 upstream of the coolant cooler 17.

FIG. 16 shows the liquid cooling system K at medium to hot operationaltemperature of the internal combustion engine 2. The first double-actingthermostatic valve 20 now closes the auxiliary cooling circuit 19 andopens the main cooling circuit 18. The second double-acting thermostaticvalve 29 is in its intermediate position, in which the first and fourthcoolant lines 22, 27 are open, permitting coolant to flow from the firstcoolant line 22 into the free part 19 a of the auxiliary cooling circuit19 as well as into the fourth coolant line 27. Thus the first and thirdcooling space 5, 8 will receive coolant flow. From the first coolingspace 5 of the cylinder head 3 the coolant flows via the first andfourth coolant line 22, 27 into the third cooling space 8 of thecylinder block 4 and leaves the cylinder block 4 via the third coolantline 24 towards the main cooling circuit 18 upstream of the coolantcooler 17.

The oil cooler 14, the second cooling space 6 for cooling the exhaustmanifold 7 and the vehicle heating element 15 will always receivecoolant flow regardless of the positions of the thermostatic valves 20,26, 28, 29.

1. A liquid cooling system for an internal combustion engine of avehicle with a cylinder head comprising an integrated exhaust manifold,wherein the cylinder head has at least one first cooling space forcooling areas adjacent to a combustion chamber and at least one secondcooling space for cooling the exhaust manifold, said first and secondcooling spaces providing separate parallel cooling flow paths, whereinat least one oil cooler and/or at least one vehicle heating element isdisposed in a cooling circuit in series with the second cooling space.2. The liquid cooling system according to claim 1, wherein a firstpartial cooling circuit leading to the first cooling space and a secondpartial cooling circuit leading to the second cooling space branch off acommon main line.
 3. The liquid cooling system according to claim 2,wherein the oil cooler in the second partial cooling circuit is locatedupstream of the second cooling space.
 4. The liquid cooling systemaccording to claim 2, wherein the vehicle heating element in the secondpartial cooling circuit is located downstream of the second coolingspace.
 5. The liquid cooling system according to claim 1, wherein afirst double-acting thermostatic valve is disposed upstream of thecoolant pump in the area where a main cooling circuit coming from thecoolant cooler and an auxiliary cooling circuit bypassing the coolantcooler meet.
 6. The liquid cooling system according to claim 5, whereinthe first cooling space is connected with the auxiliary cooling circuitby a first coolant line.
 7. The liquid cooling system according to claim5, wherein the second cooling space is connected with the main coolingcircuit and/or the auxiliary cooling circuit by a second coolant line.8. The liquid cooling system according to claim 1, wherein at least onethird cooling space in the cylinder block is connected with the firstcooling space in the cylinder head by means of at least one transferpassage.
 9. The liquid cooling system according to claim 8, wherein thethird cooling space is connected with the main cooling circuit by meansof a third coolant line, the connection with the main cooling circuitbeing located upstream of the coolant cooler.
 10. The liquid coolingsystem according to claim 9, wherein a single-acting thermostatic valveis disposed in the third coolant line.
 11. The liquid cooling systemaccording to claim 8, wherein the third cooling space is connected withthe auxiliary cooling circuit and/or the first coolant line by means ofa fourth coolant line.
 12. The liquid cooling system according to claim11, wherein a single-acting thermostatic valve is provided in the fourthcoolant line.
 13. The liquid cooling system according to claim 11,wherein at the crossing site of the first coolant line and the fourthcoolant line and the auxiliary cooling circuit a second double-actingthermostatic valve is provided.
 14. The liquid cooling system accordingto claim 2, wherein the first partial cooling circuit and the secondpartial cooling circuit branch of the common main line downstream of acoolant pump.
 15. The liquid cooling system according to claim 7,wherein the vehicle heating element is located in the second coolantline.